1. Field of the Invention
The present invention relates to a sanitary napkin with a projection on a body surface of a main body, and more particularly to a sanitary napkin whose projection can easily be brought into contact with the a desired region of the wearer's crotch upon wearing and kept in contact with the wearer's crotch even when the main body moves during wear so as to be effective in preventing leakage of menstrual blood.
2. Description of the Related Art
There have been known sanitary napkins of the type including a main body with a liquid-absorbent layer and a projection disposed on the body surface of the main body.
Japanese Unexamined Patent Application Publication No. 2001-504727 discloses a sanitary napkin with a liquid-absorbent layer and a topsheet covering the body surface of the liquid-absorbent layer. Between the topsheet and the liquid-absorbent layer, there is provided a hump to form a projection. This hump has the ability to absorb liquid. The hump is shaped to gradually decrease in width and height toward front and rear ends. This sanitary napkin is aimed at preventing leakage of menstrual blood by keeping the hump in contact with a groove of the wearer's body from the vaginal opening to the intergluteal cleft.
Japanese Unexamined Patent Application Publication No. 2000-83993 discloses a sanitary napkin whose liquid-absorbent layer is composed of separate upper and lower cores. The lower core is integral with a liquid-impermeable lower sheet. On the body surface side of the lower core, there is provided a liquid-permeable upper sheet. Front and rear ends of the upper sheet are secured to the lower core, and elastic members are secured to the upper sheet in order to exert a longitudinal elastic contractive force. The upper core is also secured to the upper sheet. The upper core, as well as the upper sheet, can be raised from the lower core by the elastic contractive force. The upper core can face the wearer's vulva while the outer surface of the lower sheet is attached to the inner side of a crotch part of an undergarment. Japanese Unexamined Patent Application Publication No. H11-318979 discloses a sanitary napkin having a similar structure to that disclosed in JP 2000-83993.
Japanese Unexamined Patent Application Publication No. 2002-159534 discloses a sanitary product in which a narrow absorbent member, which is intended to face both the vaginal opening and the buttocks, is disposed on the body surface of a liquid retaining member with a wide absorbent core. The absorbent member is secured to the liquid retaining member at its front end, but not secured to the liquid retaining member at its rear end. This sanitary product is aimed at improving contact of the absorbent member with the wearer's crotch by adhering the rear end of the absorbent member to the wearer's body while the liquid retaining member is fixed to an inner side of an undergarment.
The sanitary napkin with the projection on the body surface of the main body may be used such that the main body is fixed to an inner side of a crotch part of an undergarment through a pressure-sensitive adhesive layer to bring the projection into contact with the vaginal opening and/or the intergluteal cleft. However, as the wearer's body moves while wearing the sanitary napkin, the undergarment is stretched or moved laterally by the motion of the buttocks. Therefore, the sanitary napkin fixed on the undergarment tends to move laterally following the deformation of the undergarment. For example, as a wearer walks with the sanitary napkin worn in the crotch, the sanitary napkin moves from side to side along with the undergarment.
In the sanitary napkin disclosed in JP 2001-504727, since the hump (or projection) is integrally formed on the body surface of the main body, the projection moves along with the main body and easily separates from the vaginal opening or the intergluteal cleft as the main body adhered to the undergarment moves along with the undergarment, creating a clearance between the wearer's body and the sanitary napkin to cause lateral or rearward leakage of menstrual blood.
In the sanitary napkin disclosed in JP 2000-83993, since the body surface of the upper core, which is to be in contact with vaginal opening, is relatively flat, there is a possibility that as the lower core moves laterally following the motion of the undergarment, the upper core also moves laterally following the motion of the lower core. Upon wearing sanitary napkin, moreover, it is required to adhere the lower core to the inner side of the crotch part of the undergarment and then pulling the sanitary napkin up toward the wearer's crotch along with the undergarment. At this time, since the lower core is concavely curved in the longitudinal direction to conform to the shape of the crotch part of the undergarment, a force to raise the upper core due to the elastic members will decrease, so that the upper core becomes liable to move over the lower core. When the sanitary napkin is pulled up and worn along with the undergarment, therefore, the upper core may be displaced laterally with respect to a target region such as the vaginal opening. This is also true for the sanitary napkin disclosed in JP H11-318979.
In the sanitary product disclosed in JP 2002-159534, only the front end of the narrow absorbent member is fixed to the liquid retaining member to leave the rear portion freely movable. Therefore, when the sanitary product is fixed to the crotch part of the undergarment and applied to the wearer's crotch along with the undergarment, it is difficult to bring the absorbent member, whose rear portion can move freely, into contact with the vaginal opening and the intergluteal cleft without fail.